The use and manufacture of foil packages is well known in the art. Foil packages are especially useful for sterile medical devices. It is known, for example, to package surgical needles and sutures in foil packages. Foil packages have the advantage of providing a gas-tight, hermetic seal, and the packages provide an impenetrable barrier to pathogens and contaminants. Foil may also be molded to the shape of the device or device package. Foil packages are typically required for medical devices that are moisture sensitive such as bioabsorbable and bioresorbable implantable devices.
Surgical sutures are typically packaged in dispenser packages that protect the suture and any attached needle(s) from damage during handling. Examples of dispenser packages for sutures are contained in U.S. Pat. Nos. 6,135,272, 6,047,815, 6,098,796 and 5,788,062, which are incorporated by reference. The dispenser package must then be inserted into a package providing a sterile barrier. In the case of a moisture sensitive device, the packaging must be gas tight as well. Foil packages for suture dispenser packages, and methods of packaging dispenser packages in outer foil pouches or packages are known in this art. Examples of outer foil packages and methods of forming such foil packages are contained in U.S. Pat. Nos. 6,021,625, 5,987,855, 5,868,244, 5,732,529, 6,097,427, 5,833,055, 5,623,810, 5,709,067 and 5,341,922, which are incorporated by reference.
A typical foil used in manufacturing foil packages is a laminate consisting of an outer polymeric film or sheet, a foil sheet and an inner polymeric film or sheet. The inner polymeric sheet is heat sensitive and can be heated at relatively low temperatures to form a heat seal with an opposed polymeric sheet of another foil. In a typical foil packaging operation, foil from rolls is fed into manufacturing apparatuses. One foil sheet is fed as the upper barrier of the package, while a second foil sheet is roll fed for use in forming the bottom sheet of the package. The sheets are arranged so that the inner polymeric sheets are opposed in order to form the interior of the package. Typically, the machinery will mold a cavity in the bottom sheet, while the top sheet is maintained as planar. After a suture dispenser package is placed in the cavity, the top and bottom foils are cut, and a partial heat seal is formed about the periphery of the package. An opening is typically left to provide for the flow of sterilant gases into the foil package. Once sterilization is complete, the opening in the package is heat sealed, thereby providing a sterile barrier. Another known method of sterilization with foil packages provides for the sealing of the periphery of the package, wherein a vent having a bio-barrier is contained in the package. Typically, two or more packages are connected to the bio-barrier vent via a manifold, and the packages are sealed except for the manifold connection. After sterilization, the manifolds are sealed and the packages are cut apart from each other and the bio-barrier vent.
While the known processes for manufacturing foil packages having molded cavities are acceptable when using foil laminate fed from rolls, there can be problems when attempting to use pre-cut sheets of laminate foil. Specifically, it is known that the laminate foil can exhibit substantial curling after the cavities are molded into the foil sheet. Such curling may interfere with the heat-sealing of a planar laminate foil top to the molded bottom laminate, thereby potentially compromising the integrity of the hermetic seal of the foil package.
Accordingly, there is a need in this art for a novel process for manufacturing foil packages with molded cavities from foil laminate sheets that prevents or substantially reduces curling.